This invention relates to piering systems used in connection with the supporting of building foundations, footings and the like. In those types of applications, as is well known to those skilled in the art, piers are hydraulically driven or forced into the ground until they encounter a substrate sufficient to bear the load necessary to support the foundation or footing under which the pier is placed. When it is necessary to reach a substantial depth, multiple pier sections assembled in a linear arrangement must be employed.
Most of the pipe piers currently in use in the piering market today are comprised of pier sections that are not permanently affixed to one another. The pipe sections are fitted together in various ways, and in most instances, those methods are entirely satisfactory. However, under certain conditions, the manner in which the pipe sections are joined becomes critical. For instance, when the pier is being driven through a void, such as a mine or cavern, pier sections which rely on a continual axial compressive load as its means of connection may fall apart unless they are adequately connected together. Also, the connection point must be able to withstand the considerable compressive load placed thereon when the pier is being driven into the ground. Pier sections which are merely screwed or bolted together may collapse under extreme compressive loads. There further exist pier systems whose pipe sections butt up end to end with each other by using threaded ends; however, these are expensive to manufacture and can be time-consuming to install.